The well-known sampling theorems of information theory are summarized in "Reference Data for Radio Engineers", fifth edition, New York 1969, pages 21-14 and 21-15, and are given in detail in H. S. Black, "Modulation Theory", Princeton 1953, pages 37 to 57 inclusive, and in P. F. Panter, "Modulation, Noise, and Spectral Analysis", New York 1965, pages 506 to 547 inclusive. We do not know of any relevant patent art, publications or apparatus, the theory of which is not fully disclosed in the above references.
These references state that 2B is the lowest sampling rate permissible for transmission and accurate reconstruction of a signal with a bandwidth B, whether the signal extends from zero to B, or from nB to (n+1) B, where n is an integer (see Black at the second paragraph of page 37 and the first paragraph of page 38; see Panter at page 507, the second and third paragraphs).